1. Field of the Invention
The present invention relates to an endoscope system for simultaneously displaying endoscopic images produced by two endoscopes on the same monitor.
2. Description of the Related Art
Parent and child scopes are sometimes employed as a unit or system for endoscopic observation of the bile duct or other small duct in a body cavity. This kind of system comprises a parent scope which has channel whose internal diameter is large enough for a child scope to run through, a child scope which is routed through the channel, a light source for supplying illumination light to the scopes for easy observation, video processors for processing video signals originating from the imaging means of the scopes, and monitors for displaying the images.
To display a parent scope image produced by a parent scope on a monitor, an electric signal originating from a charge coupled device (CCD) at the distal end of an endoscope must be converted into a video signal using a video processor. As for a child scope inserted into the channel of the parent scope, the CCD in the TV camera head mounted on the eyepiece section of the child scope forms a child scope image. Then, the electric signal resulting from the child scope image is converted into a video signal by other video processor corresponding to the child scope, then displayed on other monitor corresponding to the child scope.
For observation using parent scopes, electronic endoscope systems are needed for each of the parent scopes. This results in an increase in the space occupied by the endoscope systems within an endoscope room. The installation site for monitors, in particular, is restricted. That is to say, monitors must be installed in a place where operators can view them easily. However, a space wide enough to install two monitors is sometimes unavailable.
U.S. Pat. No. 4,920,413 has disclosed a system in which an X-ray image obtained in vitro and an angioscopic image obtained in vivo can be displayed on a shared monitor. The X-ray image is a fluoroscopic image obtained in vitro, which cannot be used to route an endoscope into a complicated region in a body. In addition, an object to be observed cannot be observed directly. Therefore, this system is unsuitable for detailed observation or treatment of an object.